Removing interfering contaminations from gelatin lifters

Gelatin lifter is widely used for recovering shoeprints from crime scenes. Dusty shoeprints removed from paper with loose fibers, cloth or plasterboard, might be concealed by the detached fibers. A novel technique to clean the gelatin lifter from the interfering contaminations, using adhesive lifters, was developed. The adhesive lifter is applied directly on the surface of the gelatin lifter, and is removed instantly. The adhesive lifter removes the upper layer of the attached material on the gelatin lifter. After removing the concealing material from the hidden imprint, the quality of the visualized imprint is improved. The cleaning process can be applied as many times as needed and the optimum number is different for each substrate. The small dust particles comprising the shoeprint remained attached to the sticky side of the gelatin lifter even though the adhesion force applied by the adhesive lifter is great. Repeating the procedure too many times could harm the quality of the print severely, yet the advantages of this method are greater than the risks of relocation of image quality reduction.     

A comparative research of two lifting methods: electrostatic lifter and gelatin lifter

Two-dimensional dust shoeprints are often of very high resolution and contain unique features. Lifting these prints in the most effective method may contribute much to preserving these fine details. A research was conducted by experts from Israel and Switzerland to compare gelatin lifters and electrostatic lifters for lifting shoeprints. Several substrates were chosen, and on each material a set of dry dust shoeprints was made. A set of wet prints was made on paper as well. The shoeprints were approximately of the same quality, and the only variable was the nature of the material. On substrates indifferent to the method used, the preferable sequence was tested. Gelatin lifter was superior on most substrates and for wet prints. The superior sequence for using both methods is electrostatic lifting followed by gelatin lifter.     

Experimental study of the expansion dynamic of 9 mm Parabellum hollow point projectiles in ballistic gelatin

We study in this paper the expanding behaviour of hollow point 9 mm Parabellum projectiles (Hornady XTP(?) and Speer Gold Dot(?)). We defined a deformation rate that takes into account both the diameter increase and the length reduction. We plotted the behaviour of this parameter versus impact velocity (we refer to this curve as the expanding law). This expanding law has been plotted for different gelatin weight ratios and different gelatin block lengths. We completed our experiments with a set of high speed movies in order to correlate the deceleration to the state of expansion and size of the temporary cavity. Our results pointed out that full expansion is reached shortly after the projectile fully penetrates the gelatin. This result shows that the key point to accurately simulate human body interaction with a hollow point projectile is to accurately simulate the interface (skin, skull, clothes thoracic walls). Simulating accurately organs is only an issue if a quantitative comparison between penetration depths is required, but not if we only focus on the state of expansion of the projectile. By varying the gelatin parameters, we discovered that the expanding law exhibits a velocity threshold below which no expansion occurs, followed by a rather linear curve. The parameters of that expanding law (velocity threshold and line slope) vary with the gelatin parameters, but our quantitative results demonstrate that these parameters are not extremely critical. Finally, our experiments demonstrate that the knowledge of the expansion law can be a useful tool to investigate a gunshot in a human body with a semi-jacketed projectile, giving an estimation of the impact velocity and thus the shooting distance.     

Lifting shoeprints using gelatin lifters and a hydraulic press

A method for lifting two-dimensional dust footwear marks on rough or porous surfaces, such as cardboard or cloth, using a hydraulic press, was examined. It was found that exerting pressure on the lifter by the press usually improves the quality of the results. When the shoeprints were on rough or soft surfaces, the prints transferred to the gelatin lifters were better than those obtained by the conventional method. In other cases, using the press did not improve the results but was much simpler to apply. Based on the results of this study, the hydraulic press/gelatin lifter method (the "press method") is used at the authors' laboratory, depending on the surface from which the shoeprint is to be lifted. It is the authors' intention to apply the method to other surfaces after finding the optimal pressure for surfaces with loose fibers.     

The effects of certain intermediary target materials and their proximity to ballistic gelatin on jacketed hollow point bullet expansion

Expanding bullets are preferred by law enforcement because of their wounding potential and ability to avoid over-penetration which could result in unintended targets being struck by bullets that perforate their intended targets. Expansion failure for jacketed hollow point (JHP) bullets is commonly attributed to several causes including damage to the bullet's cavity, velocity loss, bullet destabilization and materials from intermediate targets filling the bullet's cavity which can cause expansion failure when the bullet subsequently impacts a soft, fluid-based target such as human tissue or ballistic gelatin. In this study, JHP bullets were fired into ballistic gelatin after passing through selected intermediate targets representing items common to shooting incidents. Velocity loss and bullet destabilization were not factors that contributed to the JHP bullets that experienced expansion failure; however, materials obstructing the bullets' cavities and damage to the bullets' cavities were considered causes for some of the JHP bullet expansion failures. It was determined through this research that most of the target materials caused JHP bullet expansion failure when shored against the ballistic gelatin, but when placed at distances of 7 ft. from the ballistic gelatin, bullets fired through the same target materials did expand. This original and unique study produced findings that are of significant value to shooting incident reconstruction experts and other forensic professionals as shooting incidents can call into question a victim's proximity to a wall or door when a bullet(s) perforated such a target material.     

Lifting techniques for finger marks on human skin previous enhancement by Swedish Black powder — A preliminary study

An examination was done to investigate whether certain lifting techniques can lift recovered latent fingerprints on human skin surfaces of living subjects. For recovery Swedish Soot powder mixture (Swedish Black) was used.Donors intentionally placed fingerprints on the skin surface of living subjects. Finger marks were then in all cases recovered with Swedish Black powder. The procedure was repeated after 1 h and 4 h. Treated finger marks were secured and preserved as latent fingerprint evidence by different lifting processes. Having examined skin surfaces and finger marks we observed that the lifters such as white instant lifter, white fingerprint gelatin, black fingerprint gelatin, silicone, transparent adhesive tape, are suitable. Moreover, white fingerprint gelatin and white instant lifter proved to be very good at lifting treated finger marks. Black fingerprint gelatin was very good also, but finger marks were examined by slant light.     

The Effects of Polymer Pigmentation on Fingermark Development Techniques

The effectiveness of latent fingerprint development techniques is heavily influenced by the physical and chemical properties of the deposition surface. The use of powder suspensions is increasing for development of prints on a range of surfaces. We demonstrate that carbon powder suspension development on polymers is detrimentally affected by the presence of common white pigment, titanium dioxide. Scanning electron microscopy demonstrates that patches of the compound are clearly associated with increased levels of powder adhesion. Substrates with nonlocalized titanium dioxide content also exhibit increased levels of carbon powder staining on a surface‐wide basis. Secondary ion mass spectrometry and complementary techniques demonstrate the importance of levels of the pigment within the top 30 nm. The association is independent of fingermark deposition and may be related to surface energy variation. The detrimental effect of the pigment is not observed with small‐particle reagent (MoS₂ SPR) or cyanoacrylate (superglue) fuming techniques that exploit different development mechanisms.     

Penetration Depth of Projectiles Fired from a Replica of Colt Navy of 1851 in 20% Gelatin Blocks Correlated with Fatal Injuries Assessed in an Autopsy of a 78‐Year‐Old Man

Pursuant to the Polish Weapons and Ammunitions Law, muzzle‐loading black powder weapons, manufactured before 1885, or their replicas, as well as suitable projectiles, can be possessed legally without registration and special licenses. The aim of the study was to assess the penetration depth of projectiles fired from a black powder weapon, replica of Colt Navy of 1851, in 20% gelatin blocks and to compare the obtained results with the actual injuries found on autopsy of a 78‐year‐old man who had committed suicide. In the experiments, we used the black powder weapon and ammunitions, as well as gelatin blocks serving as a soft tissue model. We ascertained that solid spherical projectiles fired from black powder weapons cause extensive injuries, especially in the initial segment of the wound canal. Additionally, based on the presence and location of the wad in the wound canal, the distance from which the shot was fired can be determined.     

Non-biased lineup instructions do matter – a problem for older witnesses

Abstract

From the limited literature on older witnesses’ identification performance it is known that they are less accurate on lineups compared to younger witnesses. What is less certain is why they show this age deficit and what can be done to aid their performance. Witnesses forgot being given non-biased lineup instructions informing witnesses that the perpetrator may or may not be present. More older witnesses than younger witnesses forgot and witnesses who failed to report remembering these instructions were significantly less accurate on the lineups. In addition, the current study investigated the use of sequential lineup presentation and stringent decision criteria to aid the performance of older witnesses. Sequential presentation was beneficial to both younger and older adults when the lineup was target absent (TA) but was detrimental when the lineup was target present (TP). Stringent decision criteria had no significant beneficial effect. Future directions for aiding older witnesses’ performance are discussed.     

Comparison of the terminal ballistics of full metal jacket 7.62-mm M80 (NATO) and 5.56-mm M193 military bullets: a study in ordnance gelatin

Great controversy has surrounded the replacement of the 7.62-mm caliber by the reduced 5.56-mm caliber as the standard U.S. military rifle. Although its relevance to human wounding can be debated, the terminal ballistics of military small arms in ordnance gelatin remains a convenient medium for comparative testing. In the present study, 7- by 10- by 24-in. (18 by 25 by 61 cm) blocks of 20% ordnance gelatin were fired upon from a range of 19 ft (6 m) under high-speed cinemagraphic surveillance. The tendency of the M193 5.56-mm full metal jacket projectile to break up in soft tissue simulant was confirmed as a fundamental difference from the 7.62-mm M80 NATO ball.     

Does counterfeiting benefit genuine manufacturer? The role of production costs

A monopolist sells a luxury genuine product which can be illegally copied and sold by a competitive fringe of counterfeiters. Fines imposed on caught counterfeiters are pocketed by the genuine firm. We prove that if production costs are low, then the genuine manufacturer would lobbying for high penalties so that counterfeiters should be thrown out of the market. In this case, the presence of counterfeiters does not provide any benefit to the producer of the original product. Whenever the production cost is neither too high nor too low, the optimal fine guarantees a positive demand for the genuine product as well as for the fake; the genuine producer is better off than in a world without counterfeiters. If production costs are too high, the genuine firm has no more incentive to produce. Its remaining goal is to collect penalty money from counterfeiters. Again, the presence of counterfeiters provides a benefit to the genuine manufacturer. Finally, a comparison between full protection and null protection policies is performed.     

Why is methenamine detected in Goma-2 dynamites originally methenamine free? An interpretation of relevant forensic results

After the train bombing in Madrid (Spain) on 11 March 2004, methenamine was detected in some of the specimens of Goma-2 ECO dynamite submitted to the forensic laboratories when analyzed by gas chromatography coupled with mass spectrometry detection (GC-MS). Methenamine is synthesized from formaldehyde and ammonia through a condensation reaction. However, neither methenamine nor any of these compounds were used to manufacture Goma-2 ECO dynamite. Four different experiments were designed in order to explain the presence of methenamine detected in the dynamite samples analyzed. In the first one, GC-MS was used to analyze the individual components of Goma-2 ECO provided by the manufacturer and the components mixed in a raw paste. Methenamine was detected in the manufacturer's ammonium nitrate and in the raw paste. The other experiments were designed to find the precursors sources for methenamine generation in Goma-2 ECO. Results revealed that these sources could be ammonium nitrate for ammonia and sawdust for formaldehyde. Under heating conditions, dynamite could produce these precursors, which could condense in the injection port of the GC-MS system and generate methenamine. However, methenamine was not always detected in these dynamites. This was explained by the existence of two opposite effects: (a) dynamite stability makes difficult that ammonium nitrate releases ammonia and (b) there is a gradual loss of formaldehyde in sawdust along the time. Both effects can prevent the formation of an amount of methenamine large enough to be detected.     

Potential Use in Forensics of a Novel Hybrid Gelatin—Dynamic Impact Assessment

Ballistic gelatin as simulant of the human body and organs is a support in forensics. After having obtained very good results for a new gelatin‐based composite in terms of physicochemical and rheological properties, this study focused on this material's mechanical behavior during stabbing and shooting versus bovine and porcine organs and standard ballistic gelatin. The hybrid gelatin has a predominantly elastic behavior at 23°C, whereas the elastic modulus becomes practically constant in the 10–0.1 Hz frequency range. In terms of stabbing behavior, the small variations obtained between porcine organs and surrogate are below 5%, the perforation indicating a good similarity. From the ballistic test results using 10 × 28T rubber balls, it has been seen that the hybrid ballistic gelatin conducts to more reliable and reproducible values of perforation/penetration versus standard gelatin, making from it a real candidate for use in forensic tests.     

Vapor-phase staining of cyanoacrylate-fumed latent fingerprints using p-dimethylaminobenzaldehyde

Contrasting or enhancing of cyanoacrylate ester-fumed latent fingerprints deposited on solvent-sensitive materials such as oil marker writings and rough surface materials such as unglazed earthenware is not easy by conventional dye solutions dipping or dye powder dusting. In this study, a new vapor-phase staining method using p-dimethylaminobenzaldehyde (DMAB) is proposed for staining such materials. DMAB has high volatility and selective absorbability to cyanoacrylate-fumed fingerprints, so that cyanoacrylate-treated samples can be easily stained by leaving them simply in a closed container along with DMAB crystals for 48-96 h at room temperature or in conjunction with the use of mild heating. The stained fingerprint could be excited by UV irradiation (365 nm), and the fluorescent fingerprint was photographed through a UV cut-off filter (420 nm). The new method achieved minimally destructive fluorescent staining for the solvent-sensitive samples and the rough surfaced samples.     

Analysis of potassium permanganate as addictive drug "precursor"

Potassium permanganate is used for the production of cocaine and methylcathinone. The third convention of the UN against narcotic drugs (1988) contains a list of so-called precursors, substances commonly used for the production of narcotic drugs. The control of the precursors can be a very important step to prevent the illicit production of narcotic substances. A chemical characterization of a seized product may contribute to determine the origin of the producing company and the trade channels and to prevent further illicit deliveries. 31 samples of permanganate (19 authentic and 12 seized samples) have been analyzed for 9 metallic elements. Detailed procedures for the emission spectrography and ICP-analysis are given and the range of concentrations is tabulated. It was surprising that no significant concentrations of metals like chromium, nickel or cobalt were present. Nor was the difference between the technical and analytically pure products sufficient to make a differentiation according to origin. This is probably attributable to the technical manufacture of permanganate by electrolysis. All the statistical analyses of the results performed on the available data do not allow conclusions as to the country of origin or manufacturer, as production batches of one and the same manufacturer may also show differences. Only the morphology of the product (crystals, powder or "free flowing") allows a certain characterization. Nevertheless it seems necessary to analyze all seized samples for impurities and to establish a table of "impurity profiling" in the future in order to receive more information and to find correlations in selected cases.     

Physical match: insole and shoe

In this case report, the authors show an interesting case of a physical match between an insole and a suspect shoe that was connected to the crime scene by a blood drop. Several pairs of shoes were seized and inspected. On the insoles of the main suspect's shoes, two different types of prints were seen, one was clear and the other image was faint. A physical match examination was conducted and the authors could place the right insole inside the right shoe. The insole was apparently glued to the shoe by the sweat, heat and dirt inside the shoe, and not by the manufacturer. In this case, the critical questions were how conclusive can the complexity of the random contours be, and whether the physical match between the two objects could pass the "Daubert challenge."     

Fingermarks development on gloves: Relative efficiency of 1,2 Indanedione/ZnCl2, ninhydrin and wet powder

Powder suspensions such as wet powder are used to develop fingermarks on adhesive surfaces. They can also be used on gloves but these ready-to-use commercial pre-mixed solutions are not entirely satisfactory. Among other things, they generate some background noise that can sometimes be substantial and make the exploitation of the fingermarks difficult. Recent studies have proven the effectiveness of a HFE ninhydrin solution on some types of gloves. Ninhydrin and 1,2-indanedione are reagents that are commonly used for the visualisation of fingermarks on porous and semi-porous substrates. Applying them on gloves might help to overcome the issue of background noise being produced by powder suspensions. In this study, several formulations of ninhydrin and 1,2-indanedione are compared to wet powder on a sample of nitrile, latex and vinyl gloves. The subsequent results show a greater effectiveness with the use of wet powder.     

2 fatalities due to hyperthermia in infancy. A contribution to forensic medicine case reports of death caused by heat

Two infants aged 4 1/2 and 8 months are reported to have been exposed to overheating by an electric blanket and a heating fan in bed for a period of up to approx. 19 hours. Dehydration complicated the effects of overheating. Due to the case history in combination with the autopsy and histological findings as well as the absence of toxicological findings the following diagnosis could be established: "Death from exhaustion as a consequence of long-lasting heat effect and dehydration." The necessity of thorough investigations in causes of death during infancy is shown by means of the two cases above. If possible, the rectal temperature should already be taken by the coroner. The public should get informed about the risks caused by the use of electric cushions, heating fans as well as floorboard heating.     

Experimental Effect of Shots Caused by Projectiles Fired from Air Guns with Kinetic Energy Below 17 J

Pursuant to the Polish Weapons and Ammunitions Law (Legal Gazette No 53/1999 item 549 with subsequent amendments), air guns with kinetic energy of the fired projectiles below 17 J are not regarded as weapons. The aim of the study was to assess the potential effect of shots caused by projectiles of various mass and structure fired from air guns with kinetic energy below 17 J on human soft tissues. As a model of soft tissue, we used 20% gelatin blocks. After shooting, we measured the depth of gelatin block penetration by pellets fired from various distances and compared these results with autopsy findings. The results demonstrated that examined pneumatic guns may cause serious injuries, including damage to the pleura, pericardium, liver, spleen, kidneys, femoral artery, and thoracic and abdominal aorta. Experiment shown that gelatin blocks do not reflect fully the properties of the human body.